Buffered antiperspirant compositions



2,814,584 BUFFERED TIPERSPHRANT COMPOSITIONS Edwin William Daley, Cincinnati, Ohio, assignor to The Procter & Gamble Company, Cincinnati, Ohio, a corporation of Ohio No Drawing. Application April 30, 1954, Serial No. 426,931

9 Claims. (Cl. 167-90) This invention relates to anti-perspirant compositions.

More particularly, this invention relates to highly effective anti-perspirant compositions which are substantially non-irritating to the skin and non-corrosive to textiles.

Cosmetic preparations which have a perspiration inhibiting or retarding effect are well known. Many chemical compounds capable of preventing or retarding the exudation of perspiration have been used or suggested for use in such compositions. Among these may be mentioned tartaric acid, benzoic acid, chromic acid, boric acid, salts of salicylic acid, and various salts of zinc, iron and aluminum. The aluminum salts of strong acids, and especially the chloride and sulphate, are normally considered to be the most efficacious and find the most widespread use. More recently, various derivatives of zirconium have been suggested for anti-perspirant applications and in many respects are superior to the corresponding aluminum salts.

Many of the aforementioned compounds however, exhibit characteristics which detract from their value as anti-perspirants and which militate against their extended use. taric acid, boric acid, benzoic acid and the salts of salicylic acid are relatively ineflicient; the zinc salts are irritating to the skin and the iron salts tend to discolor gabrics. Also, the aluminum and zirconium salts which are the most effective anti-perspirants (usually.the salts of strong acids) have the disadvantage of forming strongly acid solutions and thus the use of these materials in anti-perspirant preparations may result in irritation to the skin and damage to clothing. Moreover, the use of the salts of weak acids offers no solution to this problem since such compounds are relatively ineffective in inhibiting the flow of perspiration. In general, decreasing acidity of the anti-perspirant compounds is accompanied by decreasing anti-perspirant efficacy.

It is an object of this invention to provide a, composition which is highly effective in inhibiting or retarding the exudation of perspiration.

A further object of the invention is to provide a composition which is highly efiective in inhibiting orretarding the exudation of perspiration and yet which is non-irritating to the skin and non-corrosive to textiles.

A still further object is the provision of an anti-perspirant composition containing a zirconium or hafnium salt of a strong monobasic mineral acid as an essential active ingredient.

An additional object is the provision of a highly effective, non-irritating, and non-corrosive, anti-perspirant composition which may be easily applied in liquid, semi-liquid or other forms.

Other objects will be apparent from the following de tailed description.

I have found that the disadvantages associated with prior art compositions may be overcome and the objects of the invention may be realized by providing an antinited States Patent For example, chromic acid is relatively toxic; tar- Patented Nov. 26, 1957 perspirant composition comprising in combination an aqueous solution of a zirconium or hafnium salt of a strong monobasic mineral acid, a basic aluminum compound and urea.

As mentioned hereinbefore, various zirconium derivatives have been suggested as anti-perspirant agents. The most efiicacious of these are the salts of the strong acids and these form such strongly acid solutions that there is danger in their use. In general, it has been recognized that most compounds of zirconium, if soluble in Water, are relatively highly acid and cannot therefore safely be used alone in contact with the skin.

I have found however that the aqueous solutions of zirconium salts, and hafnium salts, of strong monobasic mineral acids may be rendered usable by treating them with certain basic aluminum compounds and urea. The basic aluminum compounds and the urea act as buffering agents to bring the pH of the solution of the zirconium or hafnium salt to a value which renders it safe for antiperspirant usage. For example, an unbuffered solution of zirconyl chloride, although very effective as an antiperspirant, has a pH of about 0.8 and is therefore unfit for general anti-perspirant use. When buffered with a basic aluminum compound and urea in accordance with my invention however the solution pH may be readily brought into the range from about 3 to about 5 with substantially no loss in the anti-perspirant effectiveness. This retention of anti-perspirant effectiveness in buffered solutions is totally unexpected since experience with the various aluminum salts commonly used as anti-perspirants has shown decreased efficacy with buifering.

Moreover, the buffered compositions of my invention are much superior in anti-perspirant effectiveness when compared with the aluminum compounds previously considered the most effective, such as, for example, aluminum chloride or aluminum chlorhydroxide.

The zirconium and hafnium compounds which have been found operative, for the purposes of my invention, and which may be used individually or in admixture, are the chlorides, bromides, iodides and nitrates. The zirconium and hafnium salts named above are very reactive when contacted with water and rapidly hydrolyze to the oxy-salt form. Thus, since the compositions of my invention contain appreciable amounts of water, any of the aforementioned zirconium or hafnium salts may be expected to be present in the oxy form, and it is to be understood that the presence of such stable forms is included within the scope of the invention.

The basic aluminum compounds with which the above hafnium and zirconium salts are combined have the general empirical formula Alz(OH)s-nXn where X is a monovalent acid anion of the group (31-, B1", 1* and N03- and n has an average value from about 0.8 to about 2. I have found that the aluminum chlorhydroxidecomplex of the formula Al (OH) Cl'xI-l O where x is about 2 finds ready application in the practice of my invention although any basic aluminum compound within the above defined limits gives satisfactory results. it is to be appreciated that these basic aluminum compounds in themselves have anti-perspirant properties.

In the compositions of my invention, the concentration of the anti-perspirant constituents, namely, the zirconium or hafnium salt plus the basic aluminum salt, may vary from about 5% to about 50% by weight, on an anhydrous basis. As a. practical matter however, I prefer that this concentration be in the range from about 10% to 30% by weight on an anhydrous basis.

Since, as pointed out above, the basic aluminum compounds have .anti-perspirant properties, the ratio of the aluminum salt to the zirconium or hafnium salt is theoretically unlimited. In order that the objects of my invention may be-achieved, however, I have found that this ratio must be controlled within certain limits. Thus, if the weight of aluminum compound is appreciably greater than the weight of the zirconium or hafnium salt the anti-perspirant properties of the combination is reduced, and if the weight of the aluminum compound is much less than the weight of the zirconium or hafnium salts the desired buffering of the solution of zirconium or hafnium salt is not achieved. The optimum anti-perspirant activity and buffering'effect may be realized if the atomic ratio of aluminum to zirconium or hafnium in the composition is in the range from about 3.5:1 to 1.5:1. With a mixture of zirconyl chloride octahydrate (ZrOClg-SHsO) and aluminum chlo'rhydroxide complex (Al2(OH)5Cl-2HaO), for example, the zirconium salt should preferably comprise from about 50 to 60% by weight of the mixture of the two and the aluminum compound from about 50 to 40% by weight, allweights being on a hydrated salt basis. Expressed on an anhydrous salt basis, the zirconium salt should preferably comprise from about 40 to 50% by weight of the mixture of the two and the aluminum compound from about 60 to 50% by weight.

Sufiicient urea is added in the preparation .of the compositions of my invention so that the concentration of urea in the final composition is from about 5% to about 50% by weight of the composition on an anhydrous basis, and an amount to prevent gelling of the composition. If amounts of urea less than 5% by Weight are used, the solution of the zirconium or hafnium salt plus the aluminum compound tend to gel Within a very short time (1 to 2 weeks) and therefore, as a practical matter, less than 5% urea is not desirable. solutions of the zirconium or hafnium salt plus the aluminum compound the maximum amount of urea that may be added is limited only by practical and/or economic considerations. For example, in an anti-perspirant preparation containing about anti-perspirant salts (zirconyl chloride plus aluminum chlorhydroxide) on a hydrated basis, the amount of urea that may be added is limited to about 50% by weight of the preparation because of solubility considerations. perspirant preparations containing urea in such high concentrations, i. e. about 50% by weight, or more where.

solubility considerations permit, tends to give rise to gelling problems upon long storage and may, for that reason have limited value where marketability of the product is a factor. For practical reasons'therefore, I prefer to keep the concentration of the urea in the range from about 10% to about 30% by weight of the anti-perspirant preparation, on an anhydrous basis.

With regard to the anti-perspirant compositions of my invention it is significant to point out that the urea alone is not a satisfactory buffering agent for the aforementioned zirconium or hafnium salts. Solutions of such salts when buffered with urea to pH values of 3 or higher decompose after standing several days and the zirconium or hafnium precipitates. In contrast, when the combination of urea and a basic aluminum compound is used as the buffering agent, as hereinbefore described, the zirconium or hafnium salt in aqueous solution is quite stable and remains free of precipitate for long periods of time.

Prevention of gelling of the anti-perspirant preparations is extremely important since gels have been found to have such extremely limited anti-perspirant properties as to be considered useless from a practical standpoint.

In freshly prepared However, anti- The anti-perspirant compositions of my invention may be formulated into cosmetic preparations which are in liquid, semi-liquid or other forms, the water in the cosmetic preparation comprising from about 25% 'to by weight thereof. Representative formulas for a cream type, a lotion type and a liquid antieperspirant utilizing zirconyl chloride octahydrate and aluminum chlorhydroxide complex as the active anti-perspirantconstituents are set forth below.

4 (Dream: Parts by weight Zirconyl chloride octahydrate 7.5 Aluminum chlorhydroxide complex 7. 5 Urea 18.0 Glycerine 3.0 Spermaceti wax 4.2

Tegacid (glyceryl monostearate plus 5% sapamine) 12.0 Cetyl alcohol 1.2 Water 40.4 Ethanol 5.0 Atlas 6-2152 (polyoxyalkylene stearate) 0.6 Atlas G2l60 (polyoxyalkylene propylene glycol monostearate) 0.6 Perfume q. s.

Lotion:

Zirconyl chloride octahydrate 7.5 Aluminum chlorhydroxide complex 7.5 Urea 25.0 Veegum 2.5 Ethanol 3.5 Water 46.8 Light mineral "oil 4.2 Stearyl alcohol 1.0 Atlas 6-2152 1.0 Atlas G-2'160 1.0 Perfume q. s.

Liquid:

Zirconyl chloride octahydrate 8.0 Aluminum chlorhydroxide complex 7.0 Urea 20.0 Ethanol 30.0 Water 34.0 Triton X400 (stearyl dimethyl benzyl ammonium chloride) 1.0 Perfume q. s.

It is to be understood that in the above compositions the ingredients other than the zirconium and aluminum salts and urea have been added, not for their antiperspirant characteristics, but to "obtain a product having properties which are desirable from a purely cosmetic standpoint. Also, if desired, various bacteriostatic, germicidal and/or deodorizing agents may be added in the preparation of these anti-perspirant cosmetic preparations. Typical of such additives are hexachlorophene (2,2'-dihydroxy-3,5,6-3,5,6-hexachloro diphenyl methane) or the quaternary ammonium salts such as Hyamine 1622 (para diisobutyl phenoxy ethoxy ethyl dimethyl benzyl ammonium chloride mono-hydrate). The use of these and other additives is optional, and while contemplated in the commercial practice of the invention, is not claimed as essential to the anti-perspirant function of the composition.

In preferred compositions of my invention the concentration of the "water-soluble salt of the zirconium or hafnium is from about 3% to about 30% by weight and the-concentration-of the basic aluminum compound from about 2% to about 20% by weight, all on an anhydrous basis. Optimum results are achieved when the atomic ratio of aluminum to zirconium or hafnium is within the r'ange from about 3:1 and 2:1 and when the concentration of zirconium or hafnium salt is from about 4% to about 20% and the concentration of the basic aluminum compound is from about 4% to about 15%, all concentrations being expressed by weight on an anhydrous basis. In all cases, however, the proportions of all the constituents of mycosmetic preparations should be so related that the pH of the composition is in the range fromabout 3 toabout 5 and preferably in the range from about 3.5 to about 4.5.

-As a precautionarymeasure, during and after the formulation of the anti-perspirant preparations of my invention, temperatures in'excess'of F. must-be avoided to prevent decomposition of the urea. Prolonged exposure of the preparations to temperatures above about 110 F. should likewise be avoided lest gelation of the preparations occur.

In the following examples, which are by way of illustration only, the eflicacy of the various anti-perspirant compounds was determined as follows. I

The backs of human subjects were washed with soap and water and a number of cotton disks, about 1 /2 inches in diameter, were placed on the back. Each disk was then saturated with a solution of the anti-perspirant to be tested. The saturated patches were left in place for five minutes, then removed and each test area was blotted dry with a towel.

After six hours the back was coated with an indicating cream made up of sodium carbonate, phenolphthalein and an oleaginous base, and the subject was exposed to an environment of heat and high humidity to induce sweating. This indicating cream turns a bright red wherever a droplet of perspiration appears. Thus, in areas where effective anti-perspirants had been applied only a few drops of perspiration appeared, the resultant few bright red droplets contrasting these areas with the surrounding untreated areas which showed a high proportion of the red droplets.

After the sweat pattern was fully developed a photograph of the subjects back was made. 8 x 10 inch prints of these photographs were obtained so that the test areas on the prints were about one inch in diameter. The number of sweat droplets appearing in a square one-half inch on a side were counted on each test area and a count of the number of sweat droplets in an equal-sized but untreated area was also made. The percentage reduction in sweating was then determined by a comparison of the count for the untreated area with the count for a treated area.

Example 1.Two anti-perspirant solutions having the following approximate compositions were prepared:

Solution A: Percent Zirconylchloride octahydrate 7.14 Aluminum chlorhydroxide complex 7.14 Urea 28.56 Water 57.16

Solution B:

Zirconyl chloride octahydrate Aluminum chlorhydroxide complex 8.33 Urea 50.00 Water 33.34

These solutions were tested for anti-perspirant eflicacy according to the foregoing method. A 20% solution of aluminum chloride, which is generally accepted as being an effective anti-perspirant, was used as the control sample. The results appearing in the table below are the average values from about fifteen separate determinations.

pH at: preparation Percent reduction in sweating Solution It is apparent from the above data that the zirconyl compound is a highly effective anti-perspirant although its high acidity makes it impractical of use.

A comparison of the pH and percent reduction in sweating values for zirconyl chloride octahydrate in Example 2 with the corresponding values of solutions A and B in Example 1 will clearly show that the compositions of my invention offer a practical solution to the problem of controlling the acidity of zirconium and hafnium salts while at the same time preserving their effective anti-perspirant action.

Example 3.-A series of determinations was made, according to the hereinbefore described method, of the anti-perspirant eificacy of 10% solutions of the materials listed in the table below with the indicated results.

Here again, a comparison of the pH and percent reduc tion in sweating values for the zirconyl compounds in the table above with corresponding values of solutions A and B in Example 1 indicate clearly that the compositions of my invention olfer a practical solution to the problem of controlling the acidity of the zirconyl salts while at the same time preserving their high anti-perspirant effectiveness.

The anti-perspirantcompositions of my invention are characterized by a slowly rising pH upon aging. Thus, an anti-perspirant preparation comprising 8.33% zirconyl chloride octahydrate, 8.33% aluminum chlorhydroxide complex, 50.00% urea and 33.34% water had a pH of 3.60 when prepared, a pH of 3.97 after 60 days and a pH of 4.65 after days. It is the general pattern with known anti-perspirants that a rise in pH, or increasing basicity, is accompanied by decreased anti-perspirant efficacy and this is substantiated by a comparison of the two zirconium salts in the example above. Thus, it would be expected that the anti-perspirants of my invention would substantially decrease in efiicacy as the pH rose. This, however, did not prove to be the case and the efficacy remained substantially the same regardless of the pH increase. For example, the above described composition was tested for efficacy on seven subjects and gave an average percent reduction in sweating of 77.4%. On retesting, after the pH had risen to above 4.0, the average percent reduction in sweating was 73.0. This retention of anti-perspirant efiicacy by the composition of my invention was wholly unpredictable and particularly in view of the values obtained with a 20% aluminum chloride solution as a control sample, which were respectively 61.2% and 41.0% on the original and delayed tests.

It is to be appreciated that corresponding anti-perspirant compositions containing a hafnium salt as one of the active ingredients behave in like manner as the zirconiumcontaining compositions and hafnium salts may be substituted for the zirconium salts in any of the examples 7 contained herein, and the chlorides, bromides, iodides and nitrates may be used interchangeably, with comparable results.

Examples of hafnium containing ,anti-perspirant compositions and their pH behavior are tabulated below.

Hainium oxychloride percent 7. 5 7. 5 Aluminum chlorhydroxide 7. 5 7. 5 Urea do 5.0 25.0 (812012 .do. 80. 60. 0 pH (Initial) 2.82 3.05 pH (After 3 days) 3 73 3. 97

The pH values to be given consideration on a practical basis would be those obtained after three days. These values are well above the minimum values considered safe from the standpoint of skin irritation and clothing damage and may for comparison be contrasted with the pH of a 14% aqueous solution of hafnyl chloride octahydrate which is about 1.3 and too acid for normal antiperspirant use.

Example4.-That the zirconium salts of weak acids are ineifective anti-perspirants and thus offer no solution to the problem of high acidity in effective zirconiumcontaining anti-perspirant preparations is adequately supported by the following data. All determinations were made on 5 subjects with solutions of the material according to the above described method.

Average Solution pH percent reduction in sweating Zirconium acetate 3. 4 15.0 Zirconyl chloride 0.8 75. 0 Aluminum chloride 2. 3 30. 0 Aluminum chlorhydroxide. 4. 2 23. 0

Example 5.--Two anti-perspirant solutions having the following compositions were prepared.

Aluminum basic nitrate (as A13(OH)7(NO3)2) 7.5 Urea 15.0 Water 70.0

When tested for anti-perspirant efiicacy according to the method outlined hereinbefore Solution A, on seven subjects, caused an average percent reduction in sweating of 75.1% and Solution B, on five subjects, caused an average percent reduction in sweating of 74.6%.

Example 6.--A series of tests was made to determine the effect of variousanti-perspirants on the tensile strength of textiles. The procedure was as follows:

Cotton muslin was washed, rinsed thoroughly and ironed dry. It was then cut into strips measuring 6 inches by 21 inches. An area one inch wide was marked down the center of each strip and the area was saturated with the anti-perspirant to be tested. An identical strip containing no anti-perspirant was carried through the treatment alongwith the anti-perspirant-containing strips to serve as a control. All strips were stored for 24 hours at 70 F. and 70% relative humidity, were then ironed at 275 F. and again stored under the same conditions for three hours. At the end of this period the strips were tested for tensile strength usinga Scott tensile strength machine with one inch jaws.

Results are indicated in the table below.

Average Percent Antiperspiraut breaking loss in strength strength Control (non e) 45. 0 Solution A 1 46. 7 0 15% aluminum chlorhydroxide solution 35. 4 21 20% aluminum chloride solution 30.0 33

1 Solution A: Percent Zirconyl chloride octahydrate 9. 0 Aluminum chlorhydroxide comple 7. 0 Urea t t 12.0 Water 72. 0

It is apparent from the above data that the antiperspirant compositions of my invention would be extremely advantageous of use from the standpoint of fabric damage.

Example 7.A further series of tests was run in relation to the effect of various anti-perspirant on the tensile strength of textiles following the procedure of Example 6. Here however, the strengths of the treated muslin strips were expressed as relative to an arbitrary value of 100 which was assigned to the average breaking strength of the strips that had been treated with a commercial antiperspirant cream containing aluminum sulfate as the active anti-perspirant agent. Results are given below.

Average Relative Anti-perspirant breaking strength strength Commercial auti-perspirant Cream (Aluminum sulfate active agent) 24. 4 100 15% aluminum chlorhydroxide solution 36. 4 149 20% aluminum chloride solution 20. 5 84 Solution A 1 41. 0 168 Lotion E 42. 3 173 Solution B 3 47. 7 196 1 Same as in Example 6.

2 Active ingredients: Percent Zirconyl chloride octahydrate 8. 0 Aluminum chlorhydroxide Compl 8. 0 Urea l8. 0

Percent 3 Zirconyl chloride octahydrate 8.0

Aluminum chlorhydroxide complex- 8.0 Urea 18.0 Water G6 The outstanding retention of tensile strength by the fabrics treated with compositions of my invention is readily apparent from the above table and is ample evidence of the non-corrosive nature of these compositions.

Having thus described my invention, I claim:

1. An aqueous perspiration-inhibiting composition comprising (1) a stable water-soluble salt of a group IVB metal selected from the group consisting of hafnium and zirconium and mixtures of these and a monobasic mineral acid the anion of which is a radical selected from the group consisting of Cl, I, Br and N03, (2) a basic aluminum compound of the approximate general empirical formula Al2(OH)6nXn where X is a monovalent acid anion selected from the group consisting of C1, B1, 1*, and N03- and n has an average value from about 0.8 to about 2, and (3) urea, in an amount in the range from about 5 to about 50% by weight of the composition on an anhydrous basis and suificient to prevent gelling of the composition, the water in the composition being from about 25% to by weight, the concentration of constituents (l) and (2) together being from about 5% to about 50% by weight, on an anhydrous basis, and the proportions of said constituents (l) and (2) being so related that the atomic ratio of aluminum to the group IVB metal in the composition is between about 3.5: l and 1.5:l.

2. The composition of claim 1 wherein the concentration of the water-soluble salt of the group lVB metal is from about 3% to about 30% by weight, and the concentration of the basic aluminum compound is from about 2% to about 20% by weight, the concentration in all cases being on an anhydrous basis.

3. The composition of claim 2 wherein the concentrations of the water-soluble salt of the group IVB metal, the basic aluminum compound and the urea are such that the said constituents are completely in solution in the composition.

4. The composition of claim 2 wherein the concentration of urea is from about 10% to about 30% by weight on an anhydrous basis.

5. The composition of claim 4 wherein the atomic ratio of aluminum to the group IVB metal is between about 3:1 and 2:1.

6. The composition of claim 5 wherein. the concentration of the water-soluble salt of the group IVB metal is from about 4% to about 20% by weight on an anhydrous basis.

7. The composition of claim 6 wherein the concentration of the basic aluminum compound is from about 4% to about 15% by weight on an anhydrous basis.

8. The composition of claim 7 wherein the anion group of the water-soluble salt of the group IVB metal is Cl and the monovalent acid anion of the basic aluminum compound is Cl-.

9. An aqueous perspiration-inhibiting composition comprising (1) zirconyl chloride octahydrate, (2) a basic aluminum compound of the approximate general empirical formula AI2(OH)61IX7I, where X is a monovalent acid anion selected from the group consisting of Cl, Br 1, N03: and n has an average value of about 0.8 to about 2, and (3) urea, in an amount in the range from about 5 to about by weight of the composition on an anhydrous basis and 'suflicient to prevent gelling of the composition, the Water in the composition being from about 25% to by weight, the concentration of constituents l) and (2) together being from about 5% to about 50% by weight, on an anhydrous basis, and the proportions of said constituents (1) and (2) being so related that the atomic ratio of aluminum to zirconium inthe composition is between about 3.521 and 1.5:1.

References Cited in the file of this patent UNITED STATES PATENTS 2,118,566 Miles May 24, 1938 2,236,387 Wallace Mar. 25, 1941 2,492,085 Andersen Dec. 20, 1949 2,734,848 Berger Feb. 14, 1956 OTHER REFERENCES 

1. AN AQUEOUS PERSPIRATION-INHIBITING COMPOSITION COMPRISING (1) A STABLE WATER-SOLUBLE SALT OF A GROUP IVB METAL SELECTED FROM THE GROUP CONSISTING OF HAFNIUM AND ZIRCONIUM AND MIXTURES OF THESE AND A MONOBASIC MINERALUM AND ACID THE ANION OF WHICH IS A RADICAL SELECTED FROM THE GROUP CONSISTING OF CI,I BR AND NO3 (2) A BASIC ALUMINUM COMPOUND OF THE APPROXIMATE GENERAL EMPIRICAL FORMULA AL2(OH)8-NXN WHERE X IS A MONOVALENT ACID ANION SELECTED FROM THE GROUP CONSISTING OF CI-,BR,I-, AND N03- AND N HAS AN AVERAGE VALUE FROM ABOUT 0.8 TO ABOUT 2, AND (3) UREA, IN AN AMOUNT IN THE RANGE FROM ABOUT 5 TO ABOUT 50% BY WEIGHT OF THE COMPOSITION ON AN ANHYDROUS BASIS AND SUFFICIENT TO PREVENT GELLING OF THE COMPOSITION, THE WATER IN THE COMPOSITION BEING FROM ABOUT 25% TO 90% BY WEIGHT, THE CONCENTRATION OF CONSTITUENTS (1) AND (2) TOGETHER BEING FROM ABOUT 5, TO ABOUT 50% BY WEIGHT, ON AN ANHYDROUS BASIS, AND THE PROPORTIONS OF SAID CONSTITUENTS (1) AND (2) BEING SO RELATED THAT THE ATOMIC RATIO OF ALUMINUM TO THE GROUP IVB METAL IN THE COMPOSITION IS BETWEEN ABOUT 3.5:1 AND 1.5:1. 